1. Field of the Invention
The present invention generally relates to a method of manufacturing a semiconductor apparatus, and more particularly to a method of manufacturing a semiconductor apparatus with an internal electrical connection layer.
2. Description of Related Art
One common technique of increasing luminescence efficiency of a light-emitting diode (LED) is to use a tunnel junction to stack two or more LEDs. The stacked LEDs emit more light and are brighter than a single LED. The tunnel junction also enhances current spreading, which allows more carriers to perform recombination. Furthermore, the stacked LEDs have fewer electrodes than individual LEDs yielding the same amount of light, therefore saving space and reducing electromigration associated with the electrodes.
One conventional method of forming a tunnel junction is to employ a heavy doping technique, for example, as is disclosed in U.S. Pat. No. 6,822,991 entitled “Light Emitting Devices Including Tunnel Junctions.” As the tunnel distance of the tunnel junction is usually small, it is ordinarily difficult to achieve a desired tunnel junction via the heavy doping technique. Moreover, heavy doping may disadvantageously affect the doping concentration of a neighboring layer.
Another conventional method of forming a tunnel junction is to employ a polarization technique, for example, as disclosed in U.S. Pat. No. 6,878,975 entitled “Polarization Field Enhanced Tunnel Structures.” The polarization technique, however, requires complex process control and unduly limits fabrication material selection.
The problems described above may occur in other semiconductor devices such as solar cells or diodes. A need has thus arisen for a novel method of manufacturing a semiconductor apparatus to alleviate the problems mentioned above.